The Great White Dragon is rarely seen. Nobody knows where he slumbers, but they do know his cave is on one of the highest peaks in the world. Only few stories have made it to be Known about across the lands. Few ever made it back to there home villages to tell the story.
Nearly every primitive culture has had rituals and celebrations to guarantee the proper passage of the seasons and to ensure the fertility of crops and animals. Oversight of these ceremonies was generally the provenance of local kings or priests.
Suppose that the adventurers dispatch one of these fellows. The local peasants may become hysterical, fearing famine and death will stalk the land. Alternatively, they may want one of the new heroes to become king. For a while, this can be a good thing, but the first time that the crops fail, the superstitious locals will want to sacrifice their new leader.